Estimating natural mortality within a fisheries stock assessment model: An evaluation using simulation analysis based on twelve stock assessments

Natural mortality (M) is one of the most influential and difficult to estimate number of losses in fisheries stock assessment and management. Typically, natural mortality is estimated using indirect methods, such as correlation with measurable life history factors and rarely relies on direct data such as tagging studies. In contemporary stock assessments, natural mortality may be estimated within the model by integrating different types of data into the analysis. We evaluated the estimability of M using simulation analyses based on 12 groundfish stock assessments conducted using Stock Synthesis. The advantages of utilizing this set of peer-reviewed assessment models were that various types of data were used over a wide range of model parameterization. Our results suggest that, in many cases, M is estimable with appropriate data. Profile likelihood analyses suggested that informative length or age composition data is needed to reliably estimate M.

[1]  You‐Gan Wang.  A maximum-likelihood method for estimating natural mortality and catchability coefficient from catch-and-effort data , 1999 .

[2]  Terrance J. Quinn,et al.  Quantitative Fish Dynamics , 1999 .

[3]  Mark Nicholas Maunder.  Integration of tagging and population dynamics models in fisheries stock assessment , 1998 .

[4]  Grant G. Thompson,et al.  Confounding of Gear Selectivity and the Natural Mortality Rate in Cases where the Former is a Nonmonotone Function of Age , 1994 .

[5]  Terrance J. Quinn,et al.  Fishery Stock Assessment Models , 1998 .

[6]  D. Pauly.  On the interrelationships between natural mortality, growth parameters, and mean environmental temperature in 175 fish stocks , 1980 .

[7]  Jon T. Schnute,et al.  The influence of error on population estimates from catch-age models , 1995 .

[8]  Arni Magnusson,et al.  What makes fisheries data informative , 2007 .

[9]  D. Roff.  The Evolution of Life History Parameters in Teleosts , 1984 .

[10]  R. Hilborn,et al.  Fisheries stock assessment and decision analysis: the Bayesian approach , 1997, Reviews in Fish Biology and Fisheries.

[11]  C. Fu,et al.  Estimability of natural mortality and other population parameters in a length-based model: Pandalus borealis in Kachemak Bay, Alaska , 2000 .

[12]  David A. Fournier,et al.  A spatially disaggregated, length-based, age-structured population model of yellowfin tuna (Thunnus albacares) in the western and central Pacific Ocean , 2001 .

[13]  Richard Donald Methot,et al.  Technical description of the stock synthesis assessment program , 2000 .

[14]  R. Beverton,et al.  On the dynamics of exploited fish populations , 1993, Reviews in Fish Biology and Fisheries.

[15]  D. Robson.  THE ANALYSIS OF A CATCH CURVE , 1960 .

[16]  Eric L. Charnov,et al.  Life History Invariants: Some Explorations of Symmetry in Evolutionary Ecology , 1993 .

[17]  D. Gunderson.  Trade-off between reproductive effort and adult survival in oviparous and viviparous fishes , 1997 .

[18]  Jm Hoenig,et al.  Empirical use of longevity data to estimate mortality rates , 1983 .

[19]  A. L. Jensen.  Beverton and Holt life history invariants result from optimal trade-off of reproduction and survival , 1996 .

[20]  D. L. Alverson,et al.  A graphic review of the growth and decay of population cohorts , 1975 .

[21]  L. McDonald,et al.  Estimation of Fish Mortality , 1982 .

[22]  R. Methot,et al.  Reply to ‘The reliability of estimates of natural mortality from stock assessment models’ , 2012 .

[23]  E. Williams.  The Effects of Unaccounted Discards and Misspecified Natural Mortality on Harvest Policies Based on Estimates of Spawners per Recruit , 2002 .

[24]  K. Lorenzen.  The relationship between body weight and natural mortality in juvenile and adult fish: a comparison of natural ecosystems and aquaculture , 1996 .

[25]  David A. Fournier,et al.  MULTIFAN-CL: a length-based, age-structured model for fisheries stock assessment, with application to South Pacific albacore, Thunnus alalunga , 1998 .

[26]  William G. Clark,et al.  Effects of an erroneous natural mortality rate on a simple age-structured stock assessment , 1999 .